It has long been the practice in neurosurgery to employ a three point clamp on the head of a patient to securely locate and hold the head in place during surgery. In the prior art devices, pins mounted on one or more adjustable arms are forced into the skull of the patient to positively grip the skull so that subsequent movement is not possible. This is important in neurosurgery since, in many procedures, the patient is not fully sedated but remains conscious to enable responses to probes to be evaluated by the medical staff.
The use of three arms to support three penetrating pins introduces a complication that has proved unnecessary in the installation of the prior art skull clamps. This is the case primarily because such clamps could not provide accurate alignment of two of the skull engaging pins for all head sizes. In many arrangements, there was no possibility of aligning two oppositely disposed pins. In other systems, the ability to align two of the pins relied on the use of complicated structure that occupied an unacceptable amount of space in the vicinity of the patient's skull and was difficult to both put in place and to adjust during a surgical procedure. It is well recognized that surgical staff must have the maximum space available to move about a patient during surgery particularly in the event of unforeseen complications arising. With several available clamping apparatus, freedom of movement about the patient was curtailed due to the obstructions caused by the skull clamping apparatus.